The purchase handler is not called after calling FAPI.UI.showPayment. What to do?

Question

Classmates

When calling FAPI.UI.showPayment(), if money is debited without confirmation (additional windows with "buy"/"close" buttons), then the callback is called only by the user's action - if he pressed the close button. If he pressed the cross or clicked outside the window, then the window is closed, but the handler is not called, although the purchase was made. I think it's a clear bug. Can you advise how to handle this situation?

Answer 1

There is such a problem.
As a workaround - to make in parallel the second flow of transactions to your application from the game server that received the server callback about the completed transaction.